Bacillus coagulans restores pathogen-induced intestinal dysfunction via acetate-FFAR2-NF-[Formula: see text]B-MLCK-MLC axis in Apostichopus japonicus.

Skin ulceration syndrome (SUS) is currently the main disease threatening Apostichopus japonicus aquaculture due to its higher mortality rate and infectivity, which is caused by Vibrio splendidus. Our previous studies have demonstrated that SUS is accompanied by intestinal microbiota (IM) dysbiosis, alteration of short-chain fatty acids (SCFAs) content and the damage to the intestinal barrier. However, the mediating effect of IM on intestine dysfunction is largely unknown. Herein, we conducted comprehensive intestinal microbiota transplantation (IMT) to explore the link between IM and SUS development. Furthermore, we isolated and identified a Bacillus coagulans strain with an ability to produce acetic acid from both healthy individual and SUS individual with IM from healthy donors. We found that dysbiotic IM and intestinal barrier function in SUS recipients A. japonicus could be restored by IM from healthy donors. The B. coagulans strain could restore IM community and intestinal barrier function. Consistently, acetate supply also restores intestinal homeostasis of SUS-diseased and V. splendidus-infected A. japonicus. Mechanically, acetate was found to specifically bind to its receptor-free fatty acid receptor 2 (FFAR2) to mediate IM structure community and intestinal barrier function. Knockdown of FFAR2 by transfection of specific FFAR2 siRNA could hamper acetate-mediated intestinal homeostasis in vivo. Furthermore, we confirmed that acetate/FFAR2 could inhibit V. splendidus-activated NF-κB-MLCK-MLC signaling pathway to restore intestinal epithelium integrity and upregulated the expression of ZO-1 and Occludin. Our findings provide the first evidence that B. coagulans restores pathogen-induced intestinal barrier dysfunction via acetate/FFAR2-NF-κB-MLCK-MLC axis, which provides new insights into the control and prevention of SUS outbreak from an ecological perspective.IMPORTANCESkin ulceration syndrome (SUS) as a main disease in Apostichopus japonicus aquaculture has severely restricted the developmental A. japonicus aquaculture industry. Intestinal microbiota (IM) has been studied extensively due to its immunomodulatory properties. Short-chain fatty acids (SCFAs) as an essential signal molecule for microbial regulation of host health also have attracted wide attention. Therefore, it is beneficial to explore the link between IM and SUS for prevention and control of SUS. In the study, the contribution of IM to SUS development has been examined. Additionally, our research further validated the restoration of SCFAs on intestinal barrier dysfunction caused by SUS via isolating SCFAs-producing bacteria. Notably, this restoration might be achieved by inhibition of NF-κB-MLCK-MLC signal pathway, which could be activated by V. splendidus. These findings may have important implications for exploration of the role of IM in SUS occurrence and provide insight into the SUS treatment.

Effects of seawater acidification and warming on morphometrics and biomineralization-related gene expression during embryo-larval development of a lightly-calcified echinoderm.

CO2-induced ocean acidification and warming pose ecological threats to marine life, especially calcifying species such as echinoderms, who rely on biomineralization for skeleton formation. However, previous studies on echinoderm calcification amid climate change had a strong bias towards heavily calcified echinoderms, with little research on lightly calcified ones, such as sea cucumbers. Here, we analyzed the embryo-larval development and their biomineralization-related gene expression of a lightly calcified echinoderm, the sea cucumber (Apostichopus japonicus), under experimental seawater acidification (OA) and/or warming (OW). Results showed that OA (- 0.37 units) delayed development and decreased body size (8.58-56.25 % and 0.36-19.66 % decreases in stage duration and body length, respectively), whereas OW (+3.1 °C) accelerated development and increased body size (33.99-55.28 % increase in stage duration and 2.44-14.41 % enlargement in body length). OW buffered the negative effects of OA on the development timing and body size of A. japonicus. Additionally, no target genes were expressed in the blastula stage, and only two biomineralization genes (colp3α, cyp2) and five TFs (erg, tgif, foxN2/3, gata1/2/3, and tbr) were expressed throughout the embryo-larval development. Our findings suggest that the low calcification in A. japonicus larvae may be caused by biomineralization genes contraction, and low expression of those genes. Furthermore, this study indicated that seawater acidification and warming affect expression of biomineralization-related genes, and had an effect on body size and development rate during the embryo-larval stage in sea cucumbers. Our study is a first step toward a better understanding of the complexity of high pCO2 on calcification and helpful for revealing the adaptive strategy of less-calcified echinoderms amid climate change.

Transcriptomic Responses of a Lightly Calcified Echinoderm to Experimental Seawater Acidification and Warming during Early Development.

Ocean acidification (OA) and ocean warming (OW) are potential obstacles to the survival and growth of marine organisms, particularly those that rely on calcification. This study investigated the single and joint effects of OA and OW on sea cucumber Apostichopus japonicus larvae raised under combinations of two temperatures (19 °C or 22 °C) and two pCO2 levels (400 or 1000 µatm) that reflect the current and end-of-21st-century projected ocean scenarios. The investigation focused on assessing larval development and identifying differences in gene expression patterns at four crucial embryo-larval stages (blastula, gastrula, auricularia, and doliolaria) of sea cucumbers, using RNA-seq. Results showed the detrimental effect of OA on the early development and body growth of A. japonicus larvae and a reduction in the expression of genes associated with biomineralization, skeletogenesis, and ion homeostasis. This effect was particularly pronounced during the doliolaria stage, indicating the presence of bottlenecks in larval development at this transition phase between the larval and megalopa stages in response to OA. OW accelerated the larval development across four stages of A. japonicus, especially at the blastula and doliolaria stages, but resulted in a widespread upregulation of genes related to heat shock proteins, antioxidant defense, and immune response. Significantly, the negative effects of elevated pCO2 on the developmental process of larvae appeared to be mitigated when accompanied by increased temperatures at the expense of reduced immune resilience and increased system fragility. These findings suggest that alterations in gene expression within the larvae of A. japonicus provide a mechanism to adapt to stressors arising from a rapidly changing oceanic environment.

Midgut microbiota affects the intestinal barrier by producing short-chain fatty acids in Apostichopus japonicus.

Introduction: The intestinal microbiota participates in host physiology and pathology through metabolites, in which short-chain fatty acids (SCFAs) are considered principal products and have extensive influence on intestine homeostasis. It has been reported that skin ulceration syndrome (SUS), the disease of Apostichopus japonicus caused by Vibrio splendidus, is associated with the alteration of the intestinal microbiota composition. Method: To investigate whether the intestinal microbiota affects A. japonicus health via SCFAs, in this study, we focus on the SCFA profiling and intestinal barrier function in A. japonicus treated with V. splendidus. Results and discussion: We found that V. splendidus could destroy the mid-intestine integrity and downregulate the expression of tight junction proteins ZO-1 and occludin in A. japonicus, which further dramatically decreased microorganism abundance and altered SCFAs contents. Specifically, acetic acid is associated with the largest number of microorganisms and has a significant correlation with occludin and ZO-1 among the seven SCFAs. Furthermore, our findings showed that acetic acid could maintain the intestinal barrier function by increasing the expression of tight junction proteins and rearranging the tight junction structure by regulating F-actin in mid-intestine epithelial cells. Thus, our results provide insights into the effects of the gut microbiome and SCFAs on intestine barrier homeostasis and provide essential knowledge for intervening in SUS by targeting metabolites or the gut microbiota.

Enhancing fluoride removal from wastewater using Al/Y amended sludge biochar.

This study explored the potential of utilizing aluminum and yttrium amended (Al/Y amended) sewage sludge biochar (Al/Y-CSBC) for efficient fluoride removal from wastewater. The adsorption kinetics of fluoride on bimetallic modified Al/Y-CSBC followed the pseudo-second-order model, while the adsorption isotherm conformed to the Freundlich equation. Remarkably, the material exhibited excellent fluoride removal performance over a wide pH range, achieving a maximum adsorption capacity of 62.44 mg·g-1. Moreover, Al/Y-CSBC demonstrated exceptional reusability, maintaining 95% removal efficiency even after six regeneration cycles. The fluoride adsorption mechanism involved ion exchange, surface complexation, and electrostatic adsorption interactions. The activation and modification processes significantly increased the specific surface area of Al/Y-CSBC, leading to a high isoelectric point (pHpzc = 9.14). The incorporation of aluminum and yttrium metals exhibited a novel approach, enhancing the adsorption capacity for fluoride ions due to their strong affinity. Furthermore, the dispersing effect of biochar played a crucial role in improving defluoridation efficiency by enhancing accessibility to active sites. These findings substantiate the significant potential of Al/Y-CSBC for enhanced fluoride removal from wastewater.

Mesentery AjFGF4-AjFGFR2-ERK pathway modulates intestinal regeneration via targeting cell cycle in echinoderms.

OBJECTIVES: The purpose of the study aims to understand the regeneration process and its cytology mechanism in economic echinoderms. MATERIALS AND METHODS: The intestine regeneration process of Apostichopus japonicus was investigated by immunohistochemistry and the cell proliferation was detected by immunofluorescence and flow cytometry. Fibroblast growth factor 4 of A. japonicus (AjFGF4) was screened by RNA-seq analysis and validated to regulate cell proliferation by siAjFGF4 and recombinant-AjFGF4 treatment. The binding and co-localization of AjFGF4 and AjFGFR2 were verified by Co-IP, GST-pull down, and immunofluorescence. Then, the AjFGF4-AjFGFR2-ERK-cell cycle axis was examined by western blot, immunofluorescence, and flow cytometry techniques. RESULTS: The mesentery was served as the epicenter of intestinal regeneration via activating cell proliferation and other cellular events. Mechanically, AjFGF4-mediated cell proliferation was dependent on the binding to its receptor AjFGFR2, and then triggered the conserved ERK-MAPK pathway but not JNK and p38 pathway. The activated ERK-MAPK subsequently mediated the expression of cell cycle regulatory proteins of CDK2, Cyclin A, and Cyclin B to promote cell proliferation. CONCLUSIONS: We provide the first functional evidence that AjFGF4-AjFGFR2-ERK-cell cycle axis mediated cell proliferation was the engine for mesentery-derived intestine regeneration in echinoderms.

Gut Microbiota Mediates Skin Ulceration Syndrome Outbreak by Readjusting Lipid Metabolism in Apostichopus japonicus.

The intestinal tract is the most important location for symbiotes and pathogens, and the microbiota plays a crucial role in affecting the health of the gut and other host organs. Dysbacteriosis in the intestinal system has been proven to be significant in skin ulceration syndrome (SUS) in sea cucumbers. This study investigates whether the gut microbiota and lipid metabolites are relevant to the initiation and progression of SUS in a Vibrio-splendidus-infected sea cucumber model. The tight junction genes were downregulated and the inflammatory factor gene transcriptions were upregulated after V. splendidus infection in the intestinal tissue of the sea cucumber. V. splendidus infection modulated the gut microbiota by interacting with Psychromonas macrocephali, Propionigenium maris, Bacillus cereus, Lutibacter flavus, and Hoeflea halophila. Meanwhile, the metabolites of the long-chain fatty acids in the intestinal tissue, including triglycerides (TG), phosphatidylethanolamines (PE), and phosphatidylglycerols (PG), were altered after V. splendidus infection. V. splendidus engaged in positive interactions with PG and PE and negative interactions with specific TG. These results related to gut microbiota and metabolites can offer practical assistance in the identification of the inflammatory mechanisms related to SUS, and this study may serve as a reference for predicting the disease.

Micro Electrochemical Machining of Array Micro-Grooves Using In-Situ Disk Electrode Fabricated by Micro-WEDM.

This paper develops an array micro-grooves manufacturing method using micro electrochemical machining (ECM) with disk electrode, which is prepared by in-situ micro wire electrical discharge machining (WEDM). This technology focuses on the difficulty of array structure manufacture in micro-electro-mechanical systems (MEMS). A micro-ECM system is built based on the micro-WEDM machine to achieve high precision processing of the array micro-grooves. Since micro-WEDM has good performance in high precision machining of the rotating structure, single and multi-edge disk electrodes can be fabricated in-situ using graphite. The as-prepared disk tool electrode is directly used for micro-electrochemical milling of the array micro-grooves without disassembling away from the device, which avoids the positioning error caused by the re-clamping of the disk electrode. With the advantages of high surface quality and no electrode loss, micro-ECM improves the manufacture performance of the micro-parts. Through wire path optimization, the shape accuracy of the disk edge is improved. After the research of the micro-ECM parameters, the process is improved, and finally, the high precision array micro-grooves are obtained. This method combines the advantages of micro-WEDM and disk electrode micro-ECM milling, and it is convenient for large-scale manufacture of array micro-structures on micro-parts and MEMS.

Critical reviews of 1470-nm laser vaporization on benign prostatic hyperplasia.

Benign prostatic hyperplasia (BPH) is recognized as the common chronic disease that affect majority of men in their elder ages. Nevertheless, there are no effective documents for BPH treatment. Even though great progression has been made on BPH by laser surgery, it also faces several challenges. In this study, our aims were to explore the effects of 1470-nm laser vaporization on BPH. For the research, a total of 170 BPH patients were enrolled. A 1470-nm laser vaporization apparatus was purchased for the surgery. The indicators such as serum sodium, international prostate symptom score (IPSS), Quality of life (QOL), maximum flow rate (Qmax), prostate specific antigen (PSA), and average Post-void Residual Volume (PVR) were detected for evaluating the prostate function. The operation was successful in all 170 patients, neither of whom converted to transurethral resection of the prostate (TURP) nor to open surgery. The surgery time was 52.3 ± 5.6 min, the laser emission time was 35.6 ± 3.2 min, the energy consumption was 254.1 ± 19.3 kJ. The level of serum sodium showed no significant difference between the pre- and post-operation. Qmax was significantly increased in post-operation, while IPSS, QOL, PVR, and PSA were significantly decreased in the post-operation. The 1470-nm laser vaporization treatment protected patients against BPH, indicating that 1470-nm laser vaporization might be important on treating BPH, which provided solid foundation for further clinical treatment.